Commit aacb5d91 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

srcu: Use "ssp" instead of "sp" for srcu_struct pointer 



In RCU, the distinction between "rsp", "rnp", and "rdp" has served well
for a great many years, but in SRCU, "sp" vs. "sdp" has proven confusing.
This commit therefore renames SRCU's "sp" pointers to "ssp", so that there
is "ssp" for srcu_struct pointer, "snp" for srcu_node pointer, and "sdp"
for srcu_data pointer.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.ibm.com>
parent eb4c2382

include/linux/srcu.h

+39 −39
Original line number Diff line number Diff line
@@ -38,20 +38,20 @@ struct srcu_struct; 


#ifdef CONFIG_DEBUG_LOCK_ALLOC



int __init_srcu_struct(struct srcu_struct *sp, const char *name,

int __init_srcu_struct(struct srcu_struct *ssp, const char *name,

		       struct lock_class_key *key);



#define init_srcu_struct(sp) \

#define init_srcu_struct(ssp) \

({ \

	static struct lock_class_key __srcu_key; \

	\

	__init_srcu_struct((sp), #sp, &__srcu_key); \

	__init_srcu_struct((ssp), #ssp, &__srcu_key); \

})



#define __SRCU_DEP_MAP_INIT(srcu_name)	.dep_map = { .name = #srcu_name },

#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */



int init_srcu_struct(struct srcu_struct *sp);

int init_srcu_struct(struct srcu_struct *ssp);



#define __SRCU_DEP_MAP_INIT(srcu_name)

#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
@@ -67,28 +67,28 @@ int init_srcu_struct(struct srcu_struct *sp); 
struct srcu_struct { };

#endif



void call_srcu(struct srcu_struct *sp, struct rcu_head *head,

void call_srcu(struct srcu_struct *ssp, struct rcu_head *head,

		void (*func)(struct rcu_head *head));

void _cleanup_srcu_struct(struct srcu_struct *sp, bool quiesced);

int __srcu_read_lock(struct srcu_struct *sp) __acquires(sp);

void __srcu_read_unlock(struct srcu_struct *sp, int idx) __releases(sp);

void synchronize_srcu(struct srcu_struct *sp);

void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced);

int __srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp);

void __srcu_read_unlock(struct srcu_struct *ssp, int idx) __releases(ssp);

void synchronize_srcu(struct srcu_struct *ssp);



/**

 * cleanup_srcu_struct - deconstruct a sleep-RCU structure

 * @sp: structure to clean up.

 * @ssp: structure to clean up.

 *

 * Must invoke this after you are finished using a given srcu_struct that

 * was initialized via init_srcu_struct(), else you leak memory.

 */

static inline void cleanup_srcu_struct(struct srcu_struct *sp)

static inline void cleanup_srcu_struct(struct srcu_struct *ssp)

{

	_cleanup_srcu_struct(sp, false);

	_cleanup_srcu_struct(ssp, false);

}



/**

 * cleanup_srcu_struct_quiesced - deconstruct a quiesced sleep-RCU structure

 * @sp: structure to clean up.

 * @ssp: structure to clean up.

 *

 * Must invoke this after you are finished using a given srcu_struct that

 * was initialized via init_srcu_struct(), else you leak memory.  Also,
@@ -103,16 +103,16 @@ static inline void cleanup_srcu_struct(struct srcu_struct *sp) 
 * (with high probability, anyway), and will also cause the srcu_struct

 * to be leaked.

 */

static inline void cleanup_srcu_struct_quiesced(struct srcu_struct *sp)

static inline void cleanup_srcu_struct_quiesced(struct srcu_struct *ssp)

{

	_cleanup_srcu_struct(sp, true);

	_cleanup_srcu_struct(ssp, true);

}



#ifdef CONFIG_DEBUG_LOCK_ALLOC



/**

 * srcu_read_lock_held - might we be in SRCU read-side critical section?

 * @sp: The srcu_struct structure to check

 * @ssp: The srcu_struct structure to check

 *

 * If CONFIG_DEBUG_LOCK_ALLOC is selected, returns nonzero iff in an SRCU

 * read-side critical section.  In absence of CONFIG_DEBUG_LOCK_ALLOC,
@@ -126,16 +126,16 @@ static inline void cleanup_srcu_struct_quiesced(struct srcu_struct *sp) 
 * relies on normal RCU, it can be called from the CPU which

 * is in the idle loop from an RCU point of view or offline.

 */

static inline int srcu_read_lock_held(const struct srcu_struct *sp)

static inline int srcu_read_lock_held(const struct srcu_struct *ssp)

{

	if (!debug_lockdep_rcu_enabled())

		return 1;

	return lock_is_held(&sp->dep_map);

	return lock_is_held(&ssp->dep_map);

}



#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */



static inline int srcu_read_lock_held(const struct srcu_struct *sp)

static inline int srcu_read_lock_held(const struct srcu_struct *ssp)

{

	return 1;

}
@@ -145,7 +145,7 @@ static inline int srcu_read_lock_held(const struct srcu_struct *sp) 
/**

 * srcu_dereference_check - fetch SRCU-protected pointer for later dereferencing

 * @p: the pointer to fetch and protect for later dereferencing

 * @sp: pointer to the srcu_struct, which is used to check that we

 * @ssp: pointer to the srcu_struct, which is used to check that we

 *	really are in an SRCU read-side critical section.

 * @c: condition to check for update-side use

 *
@@ -154,32 +154,32 @@ static inline int srcu_read_lock_held(const struct srcu_struct *sp) 
 * to 1.  The @c argument will normally be a logical expression containing

 * lockdep_is_held() calls.

 */

#define srcu_dereference_check(p, sp, c) \

	__rcu_dereference_check((p), (c) || srcu_read_lock_held(sp), __rcu)

#define srcu_dereference_check(p, ssp, c) \

	__rcu_dereference_check((p), (c) || srcu_read_lock_held(ssp), __rcu)



/**

 * srcu_dereference - fetch SRCU-protected pointer for later dereferencing

 * @p: the pointer to fetch and protect for later dereferencing

 * @sp: pointer to the srcu_struct, which is used to check that we

 * @ssp: pointer to the srcu_struct, which is used to check that we

 *	really are in an SRCU read-side critical section.

 *

 * Makes rcu_dereference_check() do the dirty work.  If PROVE_RCU

 * is enabled, invoking this outside of an RCU read-side critical

 * section will result in an RCU-lockdep splat.

 */

#define srcu_dereference(p, sp) srcu_dereference_check((p), (sp), 0)

#define srcu_dereference(p, ssp) srcu_dereference_check((p), (ssp), 0)



/**

 * srcu_dereference_notrace - no tracing and no lockdep calls from here

 * @p: the pointer to fetch and protect for later dereferencing

 * @sp: pointer to the srcu_struct, which is used to check that we

 * @ssp: pointer to the srcu_struct, which is used to check that we

 *	really are in an SRCU read-side critical section.

 */

#define srcu_dereference_notrace(p, sp) srcu_dereference_check((p), (sp), 1)

#define srcu_dereference_notrace(p, ssp) srcu_dereference_check((p), (ssp), 1)



/**

 * srcu_read_lock - register a new reader for an SRCU-protected structure.

 * @sp: srcu_struct in which to register the new reader.

 * @ssp: srcu_struct in which to register the new reader.

 *

 * Enter an SRCU read-side critical section.  Note that SRCU read-side

 * critical sections may be nested.  However, it is illegal to
@@ -194,44 +194,44 @@ static inline int srcu_read_lock_held(const struct srcu_struct *sp) 
 * srcu_read_unlock() in an irq handler if the matching srcu_read_lock()

 * was invoked in process context.

 */

static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp)

static inline int srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp)

{

	int retval;



	retval = __srcu_read_lock(sp);

	rcu_lock_acquire(&(sp)->dep_map);

	retval = __srcu_read_lock(ssp);

	rcu_lock_acquire(&(ssp)->dep_map);

	return retval;

}



/* Used by tracing, cannot be traced and cannot invoke lockdep. */

static inline notrace int

srcu_read_lock_notrace(struct srcu_struct *sp) __acquires(sp)

srcu_read_lock_notrace(struct srcu_struct *ssp) __acquires(ssp)

{

	int retval;



	retval = __srcu_read_lock(sp);

	retval = __srcu_read_lock(ssp);

	return retval;

}



/**

 * srcu_read_unlock - unregister a old reader from an SRCU-protected structure.

 * @sp: srcu_struct in which to unregister the old reader.

 * @ssp: srcu_struct in which to unregister the old reader.

 * @idx: return value from corresponding srcu_read_lock().

 *

 * Exit an SRCU read-side critical section.

 */

static inline void srcu_read_unlock(struct srcu_struct *sp, int idx)

	__releases(sp)

static inline void srcu_read_unlock(struct srcu_struct *ssp, int idx)

	__releases(ssp)

{

	rcu_lock_release(&(sp)->dep_map);

	__srcu_read_unlock(sp, idx);

	rcu_lock_release(&(ssp)->dep_map);

	__srcu_read_unlock(ssp, idx);

}



/* Used by tracing, cannot be traced and cannot call lockdep. */

static inline notrace void

srcu_read_unlock_notrace(struct srcu_struct *sp, int idx) __releases(sp)

srcu_read_unlock_notrace(struct srcu_struct *ssp, int idx) __releases(ssp)

{

	__srcu_read_unlock(sp, idx);

	__srcu_read_unlock(ssp, idx);

}



/**

include/linux/srcutiny.h

+12 −12
Original line number Diff line number Diff line
@@ -60,7 +60,7 @@ void srcu_drive_gp(struct work_struct *wp); 
#define DEFINE_STATIC_SRCU(name) \

	static struct srcu_struct name = __SRCU_STRUCT_INIT(name, name)



void synchronize_srcu(struct srcu_struct *sp);

void synchronize_srcu(struct srcu_struct *ssp);



/*

 * Counts the new reader in the appropriate per-CPU element of the
@@ -68,36 +68,36 @@ void synchronize_srcu(struct srcu_struct *sp); 
 * __srcu_read_unlock() must be in the same handler instance.  Returns an

 * index that must be passed to the matching srcu_read_unlock().

 */

static inline int __srcu_read_lock(struct srcu_struct *sp)

static inline int __srcu_read_lock(struct srcu_struct *ssp)

{

	int idx;



	idx = READ_ONCE(sp->srcu_idx);

	WRITE_ONCE(sp->srcu_lock_nesting[idx], sp->srcu_lock_nesting[idx] + 1);

	idx = READ_ONCE(ssp->srcu_idx);

	WRITE_ONCE(ssp->srcu_lock_nesting[idx], ssp->srcu_lock_nesting[idx] + 1);

	return idx;

}



static inline void synchronize_srcu_expedited(struct srcu_struct *sp)

static inline void synchronize_srcu_expedited(struct srcu_struct *ssp)

{

	synchronize_srcu(sp);

	synchronize_srcu(ssp);

}



static inline void srcu_barrier(struct srcu_struct *sp)

static inline void srcu_barrier(struct srcu_struct *ssp)

{

	synchronize_srcu(sp);

	synchronize_srcu(ssp);

}



/* Defined here to avoid size increase for non-torture kernels. */

static inline void srcu_torture_stats_print(struct srcu_struct *sp,

static inline void srcu_torture_stats_print(struct srcu_struct *ssp,

					    char *tt, char *tf)

{

	int idx;



	idx = READ_ONCE(sp->srcu_idx) & 0x1;

	idx = READ_ONCE(ssp->srcu_idx) & 0x1;

	pr_alert("%s%s Tiny SRCU per-CPU(idx=%d): (%hd,%hd)\n",

		 tt, tf, idx,

		 READ_ONCE(sp->srcu_lock_nesting[!idx]),

		 READ_ONCE(sp->srcu_lock_nesting[idx]));

		 READ_ONCE(ssp->srcu_lock_nesting[!idx]),

		 READ_ONCE(ssp->srcu_lock_nesting[idx]));

}



#endif

include/linux/srcutree.h

+4 −4
Original line number Diff line number Diff line
@@ -51,7 +51,7 @@ struct srcu_data { 
	unsigned long grpmask;			/* Mask for leaf srcu_node */

						/*  ->srcu_data_have_cbs[]. */

	int cpu;

	struct srcu_struct *sp;

	struct srcu_struct *ssp;

};



/*
@@ -138,8 +138,8 @@ struct srcu_struct { 
#define DEFINE_SRCU(name)		__DEFINE_SRCU(name, /* not static */)

#define DEFINE_STATIC_SRCU(name)	__DEFINE_SRCU(name, static)



void synchronize_srcu_expedited(struct srcu_struct *sp);

void srcu_barrier(struct srcu_struct *sp);

void srcu_torture_stats_print(struct srcu_struct *sp, char *tt, char *tf);

void synchronize_srcu_expedited(struct srcu_struct *ssp);

void srcu_barrier(struct srcu_struct *ssp);

void srcu_torture_stats_print(struct srcu_struct *ssp, char *tt, char *tf);



#endif

kernel/rcu/srcutiny.c

+60 −60
Original line number Diff line number Diff line
@@ -37,30 +37,30 @@ int rcu_scheduler_active __read_mostly; 
static LIST_HEAD(srcu_boot_list);

static bool srcu_init_done;



static int init_srcu_struct_fields(struct srcu_struct *sp)

static int init_srcu_struct_fields(struct srcu_struct *ssp)

{

	sp->srcu_lock_nesting[0] = 0;

	sp->srcu_lock_nesting[1] = 0;

	init_swait_queue_head(&sp->srcu_wq);

	sp->srcu_cb_head = NULL;

	sp->srcu_cb_tail = &sp->srcu_cb_head;

	sp->srcu_gp_running = false;

	sp->srcu_gp_waiting = false;

	sp->srcu_idx = 0;

	INIT_WORK(&sp->srcu_work, srcu_drive_gp);

	INIT_LIST_HEAD(&sp->srcu_work.entry);

	ssp->srcu_lock_nesting[0] = 0;

	ssp->srcu_lock_nesting[1] = 0;

	init_swait_queue_head(&ssp->srcu_wq);

	ssp->srcu_cb_head = NULL;

	ssp->srcu_cb_tail = &ssp->srcu_cb_head;

	ssp->srcu_gp_running = false;

	ssp->srcu_gp_waiting = false;

	ssp->srcu_idx = 0;

	INIT_WORK(&ssp->srcu_work, srcu_drive_gp);

	INIT_LIST_HEAD(&ssp->srcu_work.entry);

	return 0;

}



#ifdef CONFIG_DEBUG_LOCK_ALLOC



int __init_srcu_struct(struct srcu_struct *sp, const char *name,

int __init_srcu_struct(struct srcu_struct *ssp, const char *name,

		       struct lock_class_key *key)

{

	/* Don't re-initialize a lock while it is held. */

	debug_check_no_locks_freed((void *)sp, sizeof(*sp));

	lockdep_init_map(&sp->dep_map, name, key, 0);

	return init_srcu_struct_fields(sp);

	debug_check_no_locks_freed((void *)ssp, sizeof(*ssp));

	lockdep_init_map(&ssp->dep_map, name, key, 0);

	return init_srcu_struct_fields(ssp);

}

EXPORT_SYMBOL_GPL(__init_srcu_struct);
@@ -68,15 +68,15 @@ EXPORT_SYMBOL_GPL(__init_srcu_struct); 


/*

 * init_srcu_struct - initialize a sleep-RCU structure

 * @sp: structure to initialize.

 * @ssp: structure to initialize.

 *

 * Must invoke this on a given srcu_struct before passing that srcu_struct

 * to any other function.  Each srcu_struct represents a separate domain

 * of SRCU protection.

 */

int init_srcu_struct(struct srcu_struct *sp)

int init_srcu_struct(struct srcu_struct *ssp)

{

	return init_srcu_struct_fields(sp);

	return init_srcu_struct_fields(ssp);

}

EXPORT_SYMBOL_GPL(init_srcu_struct);
@@ -84,22 +84,22 @@ EXPORT_SYMBOL_GPL(init_srcu_struct); 


/*

 * cleanup_srcu_struct - deconstruct a sleep-RCU structure

 * @sp: structure to clean up.

 * @ssp: structure to clean up.

 *

 * Must invoke this after you are finished using a given srcu_struct that

 * was initialized via init_srcu_struct(), else you leak memory.

 */

void _cleanup_srcu_struct(struct srcu_struct *sp, bool quiesced)

void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced)

{

	WARN_ON(sp->srcu_lock_nesting[0] || sp->srcu_lock_nesting[1]);

	WARN_ON(ssp->srcu_lock_nesting[0] || ssp->srcu_lock_nesting[1]);

	if (quiesced)

		WARN_ON(work_pending(&sp->srcu_work));

		WARN_ON(work_pending(&ssp->srcu_work));

	else

		flush_work(&sp->srcu_work);

	WARN_ON(sp->srcu_gp_running);

	WARN_ON(sp->srcu_gp_waiting);

	WARN_ON(sp->srcu_cb_head);

	WARN_ON(&sp->srcu_cb_head != sp->srcu_cb_tail);

		flush_work(&ssp->srcu_work);

	WARN_ON(ssp->srcu_gp_running);

	WARN_ON(ssp->srcu_gp_waiting);

	WARN_ON(ssp->srcu_cb_head);

	WARN_ON(&ssp->srcu_cb_head != ssp->srcu_cb_tail);

}

EXPORT_SYMBOL_GPL(_cleanup_srcu_struct);
@@ -107,13 +107,13 @@ EXPORT_SYMBOL_GPL(_cleanup_srcu_struct); 
 * Removes the count for the old reader from the appropriate element of

 * the srcu_struct.

 */

void __srcu_read_unlock(struct srcu_struct *sp, int idx)

void __srcu_read_unlock(struct srcu_struct *ssp, int idx)

{

	int newval = sp->srcu_lock_nesting[idx] - 1;

	int newval = ssp->srcu_lock_nesting[idx] - 1;



	WRITE_ONCE(sp->srcu_lock_nesting[idx], newval);

	if (!newval && READ_ONCE(sp->srcu_gp_waiting))

		swake_up_one(&sp->srcu_wq);

	WRITE_ONCE(ssp->srcu_lock_nesting[idx], newval);

	if (!newval && READ_ONCE(ssp->srcu_gp_waiting))

		swake_up_one(&ssp->srcu_wq);

}

EXPORT_SYMBOL_GPL(__srcu_read_unlock);
@@ -127,24 +127,24 @@ void srcu_drive_gp(struct work_struct *wp) 
	int idx;

	struct rcu_head *lh;

	struct rcu_head *rhp;

	struct srcu_struct *sp;

	struct srcu_struct *ssp;



	sp = container_of(wp, struct srcu_struct, srcu_work);

	if (sp->srcu_gp_running || !READ_ONCE(sp->srcu_cb_head))

	ssp = container_of(wp, struct srcu_struct, srcu_work);

	if (ssp->srcu_gp_running || !READ_ONCE(ssp->srcu_cb_head))

		return; /* Already running or nothing to do. */



	/* Remove recently arrived callbacks and wait for readers. */

	WRITE_ONCE(sp->srcu_gp_running, true);

	WRITE_ONCE(ssp->srcu_gp_running, true);

	local_irq_disable();

	lh = sp->srcu_cb_head;

	sp->srcu_cb_head = NULL;

	sp->srcu_cb_tail = &sp->srcu_cb_head;

	lh = ssp->srcu_cb_head;

	ssp->srcu_cb_head = NULL;

	ssp->srcu_cb_tail = &ssp->srcu_cb_head;

	local_irq_enable();

	idx = sp->srcu_idx;

	WRITE_ONCE(sp->srcu_idx, !sp->srcu_idx);

	WRITE_ONCE(sp->srcu_gp_waiting, true);  /* srcu_read_unlock() wakes! */

	swait_event_exclusive(sp->srcu_wq, !READ_ONCE(sp->srcu_lock_nesting[idx]));

	WRITE_ONCE(sp->srcu_gp_waiting, false); /* srcu_read_unlock() cheap. */

	idx = ssp->srcu_idx;

	WRITE_ONCE(ssp->srcu_idx, !ssp->srcu_idx);

	WRITE_ONCE(ssp->srcu_gp_waiting, true);  /* srcu_read_unlock() wakes! */

	swait_event_exclusive(ssp->srcu_wq, !READ_ONCE(ssp->srcu_lock_nesting[idx]));

	WRITE_ONCE(ssp->srcu_gp_waiting, false); /* srcu_read_unlock() cheap. */



	/* Invoke the callbacks we removed above. */

	while (lh) {
@@ -161,9 +161,9 @@ void srcu_drive_gp(struct work_struct *wp) 
	 * at interrupt level, but the ->srcu_gp_running checks will

	 * straighten that out.

	 */

	WRITE_ONCE(sp->srcu_gp_running, false);

	if (READ_ONCE(sp->srcu_cb_head))

		schedule_work(&sp->srcu_work);

	WRITE_ONCE(ssp->srcu_gp_running, false);

	if (READ_ONCE(ssp->srcu_cb_head))

		schedule_work(&ssp->srcu_work);

}

EXPORT_SYMBOL_GPL(srcu_drive_gp);
@@ -171,7 +171,7 @@ EXPORT_SYMBOL_GPL(srcu_drive_gp); 
 * Enqueue an SRCU callback on the specified srcu_struct structure,

 * initiating grace-period processing if it is not already running.

 */

void call_srcu(struct srcu_struct *sp, struct rcu_head *rhp,

void call_srcu(struct srcu_struct *ssp, struct rcu_head *rhp,

	       rcu_callback_t func)

{

	unsigned long flags;
@@ -179,14 +179,14 @@ void call_srcu(struct srcu_struct *sp, struct rcu_head *rhp, 
	rhp->func = func;

	rhp->next = NULL;

	local_irq_save(flags);

	*sp->srcu_cb_tail = rhp;

	sp->srcu_cb_tail = &rhp->next;

	*ssp->srcu_cb_tail = rhp;

	ssp->srcu_cb_tail = &rhp->next;

	local_irq_restore(flags);

	if (!READ_ONCE(sp->srcu_gp_running)) {

	if (!READ_ONCE(ssp->srcu_gp_running)) {

		if (likely(srcu_init_done))

			schedule_work(&sp->srcu_work);

		else if (list_empty(&sp->srcu_work.entry))

			list_add(&sp->srcu_work.entry, &srcu_boot_list);

			schedule_work(&ssp->srcu_work);

		else if (list_empty(&ssp->srcu_work.entry))

			list_add(&ssp->srcu_work.entry, &srcu_boot_list);

	}

}

EXPORT_SYMBOL_GPL(call_srcu);
@@ -194,13 +194,13 @@ EXPORT_SYMBOL_GPL(call_srcu); 
/*

 * synchronize_srcu - wait for prior SRCU read-side critical-section completion

 */

void synchronize_srcu(struct srcu_struct *sp)

void synchronize_srcu(struct srcu_struct *ssp)

{

	struct rcu_synchronize rs;



	init_rcu_head_on_stack(&rs.head);

	init_completion(&rs.completion);

	call_srcu(sp, &rs.head, wakeme_after_rcu);

	call_srcu(ssp, &rs.head, wakeme_after_rcu);

	wait_for_completion(&rs.completion);

	destroy_rcu_head_on_stack(&rs.head);

}
@@ -219,13 +219,13 @@ void __init rcu_scheduler_starting(void) 
 */

void __init srcu_init(void)

{

	struct srcu_struct *sp;

	struct srcu_struct *ssp;



	srcu_init_done = true;

	while (!list_empty(&srcu_boot_list)) {

		sp = list_first_entry(&srcu_boot_list,

		ssp = list_first_entry(&srcu_boot_list,

				      struct srcu_struct, srcu_work.entry);

		list_del_init(&sp->srcu_work.entry);

		schedule_work(&sp->srcu_work);

		list_del_init(&ssp->srcu_work.entry);

		schedule_work(&ssp->srcu_work);

	}

}

kernel/rcu/srcutree.c

+244 −244

File changed.

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